The invention relates to a semiconductor device comprising a semiconductor body having a semiconductor substrate and disposed thereon a semiconductor layer, which comprises at least one group of parallel strip-shaped conducting regions having a higher conductivity than the semiconductor layer in which they are sunk or buried and comprise strip-shaped subregions, within which doping elements are present. The invention further relates to the manufacture of such a device.
Such semiconductor devices potentially form important parts of electronic circuits or components. The strip-shaped conducting regions can serve inter alia as very small and nevertheless very good conducting connection wires between components. Additional, they can be used in components, such as field effect transistors, in which they give rise to very high transconductances due to their high conductivity as compared with bulk material while the transistor can be very small.
Such a semiconductor device and such a method of manufacturing it are known from the abstract in the English language of Japanese Kokai 63-99522 (date of publication 30-4-1988) published in Pat. Abstracts of Japan, Vol. 12, Sept. 12, 1988, No. 337 (E-657), p. 18, under number E-65718. In this publication, strip-shaped conducting regions are described, which are buried or sunk in a semiconductor layer comprising gallium arsenide. The conducting strip-shaped regions comprise strip-shaped subregions doped with silicon. These subregions are formed in that during the deposition of the semiconductor layer a strip-shaped interference pattern of soft X-ray radiation is projected onto the growing surface. At the area at which the intensity of the radiation is highest, silane in the gaseous phase is decomposed and silicon is incorporated into a strip-shaped subregion. The width of a subregion is a few tens to a few hundreds of Angstroms, depending upon the wavelength of the X-ray radiation used. The free charge carriers are then present in a wider strip-shaped conducting region, within which the strip-shaped subregion is situated.
A disadvantage of the known semiconductor device is that the smallest attainable width of the strip-shaped subregions is too large for a maximum conductivity of the conducting strip-shaped regions. Another disadvantage is that in addition to doping elements, a comparatively large quantity of semiconductor material is also incorporated into the strip-shaped subregions, as a result of which the conducting strip-shaped regions do not have maximum conductivity. Finally, a disadvantage of the known method is that it is comparatively complicated.